This application claims priority of Japanese Patent Application No. 2001-258159, filed on Aug. 28, 2001, and Japanese Patent Application No. 2002-038032, filed on Feb. 15, 2002.
1. Field of the Invention
The present invention relates to a dicing method and a dicing apparatus. More particularly, the present invention relates to a dicing method and a dicing apparatus for cutting a comparatively thick substrate.
2. Description of the Related Art
In the semiconductor manufacturing field, a dicing process for cutting a substrate, for example, a silicon wafer, on which a plurality of semiconductor devices are formed, into small dices, i.e., for dicing a substrate, is indispensable. A dicing apparatus to carry out the dicing has a disk-like blade which is rotated to cut the substrate. Abrasive grains are adhered to an outer peripheral surface of the blade of the dicing apparatus, so that a side face of a cut substrate is sometimes roughly machined due to the abrasive grains. It is possible to cut the substrate by laser light in order to make the side face of the cut substrate comparatively smooth. However, in this case, the side face of the substrate is heated and burned, and a fracture layer in machining is sometimes formed on the side face.
In order to overcome these drawbacks, it is requited that the substrate be cut using a laser light which is passed within a stream of water and is reflected by an inner wall of the stream of water, so that the laser light is impinged upon the substrate.
Nevertheless, a cutting method in which the substrate is cut by irradiating the laser light passing within a stream of water toward the substrate while reflecting the same by an inner wall of the stream of water (hereinafter called a xe2x80x9claser light-water-jet-methodxe2x80x9d) can be applied only to a comparatively thin material, for example, a material having a thickness less than about 30 micrometers, because of the power of the laser light. A substrate generally adopted in the semiconductor industry, for example, a silicon wafer has a thickness of approximately 700 micrometers. Thus, it is difficult to cut the substrate having such thickness by a cutting method in which the laser light is passed within the stream of water.
Therefore, the object of the present invention is to provide a dicing method and dicing apparatus for cutting i.e., dicing, a comparatively thick material, for example, a material having a thickness of about 700 micrometers, by the laser light-water-jet-method, without roughly machining and burning the side face.
In an embodiment of the present invention, in a dicing method for dicing a plate-like workpiece, provision is made of a dicing method for dicing a plate-like workpiece, comprising the steps of rotating a disk-like blade to form a groove in one surface of the workpiece; discharging water through a water discharging portion, toward a bottom of the groove of the one surface of the workpiece to form a stream of water; and removing the portion of the workpiece extending from the bottom of the groove to the other surface of the workpiece, by laser light which is irradiated from a laser light irradiating portion, in the stream of water, and is reflected by an inner wall of the stream of water, and is impinged upon the bottom of the groove to dice the workpiece.
Namely, according to an embodiment of the present invention, a groove is formed, in advance, in the comparatively thick material, so that the material can be machined by the laser light-water-jet-method. The laser light is spread only within a cross section of the stream of water, so that the power of laser light can be reduced, and the cut substrate can be prevented from being scattered. Thus, the possibility in which a burn, a burr and a fracture layer in machining are produced on a cut face, i.e., a diced face, can be reduced.
In another embodiment of the present invention, in a dicing apparatus for dicing the plate-like material, provision is made of a dicing apparatus for dicing a plate-like workpiece, comprising a disk-like blade which rotates to form a groove in one surface of the workpiece; a water discharging portion which discharges water toward a bottom of the groove of the one surface of the workpiece to form a stream of water; and a laser light irradiating portion which irradiates a laser light in the stream of water and impinges the laser light onto the bottom of the groove while reflecting the laser light by an inner wall of the stream of water to remove the portion of the workpiece extending from the bottom of the groove to the other surface of the workpiece, so as to dice the workpiece.
Namely, according to another embodiment of the present invention, a groove is formed, in advance, in the comparatively thick material, so that the material can be machined by the laser light-water-jet-method. The laser light is spread only within a cross section of the stream of water, so that the power of the laser light can be reduced, and the cut substrate can be prevented from being scattered. Thus, the possibility in which a burn, a burr and a fracture layer in machining are produced on a cut face, i.e., a diced face, can be reduced.
In another embodiment of the present invention, in a dicing method for dicing the plate-like workpiece, provision is made of a dicing method for dicing a plate-like workpiece, comprising the steps of rotating a disk-like blade to form a groove in one surface of the workpiece; discharging water through a water discharging portion, toward a bottom of the groove of the one surface of the workpiece to form a stream of water; and removing the portion of the workpiece extending from the bottom of the groove to the other surface of the workpiece, by a laser light which is irradiated from a laser light irradiating portion, in the stream of water and is reflected by an inner wall of the stream of water and is impinged upon the bottom of the groove to dice the workpiece.
Namely, according to another embodiment of the present invention, a groove is formed, in advance, in the comparatively thick material, so that the material can be machined by the laser light-water-jet-method. The laser light is scarcely spread, so that the power of laser light can be reduced, and the cut substrate can be prevented from being scattered. Thus, the possibility in which a burn, a burr and a fracture layer in machining are produced on a cut face, i.e., a diced face can be reduced.
In another embodiment of the present invention, in a dicing apparatus for dicing a plate-like workpiece, provision is made of a dicing apparatus for dicing a plate-like workpiece, comprising a disk-like blade which rotates to form a groove in one surface of the workpiece; a water discharging portion which discharges water toward a bottom of the groove of the one surface of the workpiece to form a stream of water; and a laser light irradiating portion which irradiates a laser light in the stream of water and impinges the laser light onto the bottom of the groove while reflecting the laser light by an inner wall of the stream of water to remove the portion of the workpiece extending from the bottom of the groove to the other surface of the workpiece, so as to dice the workpiece.
Namely, according to another embodiment of the present invention, a groove is formed, in advance, in the comparatively thick material, so that the material can be machined by the laser light-water-jet-method. The laser light is scarcely spread, so that the power of laser light can be reduced, and the cut substrate can be prevented from being scattered. Thus, the possibility in which a burn, a burr and a fracture layer in machining are produced on a cut face, i.e., a diced face, can be reduced.
These and other objects, features and advantages of the present invention will be more apparent in light of the detailed description of exemplary embodiments thereof as illustrated by the drawings.